Kernel/arch/x86/mm_virt.c

   1 /*
   2  * AcessOS Microkernel Version
   3  * mm_virt.c
   4  *
   5  * Memory Map
   6  * 0xE0 - Kernel Base
   7  * 0xF0 - Kernel Stacks
   8  * 0xFD - Fractals
   9  * 0xFE - Unused
  10  * 0xFF - System Calls / Kernel's User Code
  11  */
  12 #define DEBUG   0
  13 #define SANITY  1
  14 #include <acess.h>
  15 #include <mm_virt.h>
  16 #include <mm_phys.h>
  17 #include <proc.h>
  18
  19 #define TAB     22
  20
  21 #define KERNEL_STACKS           0xF0000000
  22 #define KERNEL_STACK_SIZE       0x00008000
  23 #define KERNEL_STACKS_END       0xFC000000
  24 #define WORKER_STACKS           0x00100000      // Thread0 Only!
  25 #define WORKER_STACK_SIZE       KERNEL_STACK_SIZE
  26 #define WORKER_STACKS_END       0xB0000000
  27 #define NUM_WORKER_STACKS       ((WORKER_STACKS_END-WORKER_STACKS)/WORKER_STACK_SIZE)
  28
  29 #define PAE_PAGE_TABLE_ADDR     0xFC000000      // 16 MiB
  30 #define PAE_PAGE_DIR_ADDR       0xFCFC0000      // 16 KiB
  31 #define PAE_PAGE_PDPT_ADDR      0xFCFC3F00      // 32 bytes
  32 #define PAE_TMP_PDPT_ADDR       0xFCFC3F20      // 32 bytes
  33 #define PAE_TMP_DIR_ADDR        0xFCFE0000      // 16 KiB
  34 #define PAE_TMP_TABLE_ADDR      0xFD000000      // 16 MiB
  35
  36 #define PAGE_TABLE_ADDR 0xFC000000
  37 #define PAGE_DIR_ADDR   0xFC3F0000
  38 #define PAGE_CR3_ADDR   0xFC3F0FC0
  39 #define TMP_CR3_ADDR    0xFC3F0FC4      // Part of core instead of temp
  40 #define TMP_DIR_ADDR    0xFC3F1000      // Same
  41 #define TMP_TABLE_ADDR  0xFC400000
  42
  43 #define HW_MAP_ADDR             0xFE000000
  44 #define HW_MAP_MAX              0xFFEF0000
  45 #define NUM_HW_PAGES    ((HW_MAP_MAX-HW_MAP_ADDR)/0x1000)
  46 #define TEMP_MAP_ADDR   0xFFEF0000      // Allows 16 "temp" pages
  47 #define NUM_TEMP_PAGES  16
  48 #define LAST_BLOCK_ADDR 0xFFFF0000      // Free space for kernel provided user code/ *(-1) protection
  49
  50 #define PF_PRESENT      0x1
  51 #define PF_WRITE        0x2
  52 #define PF_USER         0x4
  53 #define PF_GLOBAL       0x80
  54 #define PF_COW          0x200
  55 #define PF_NOPAGE       0x400
  56
  57 #define INVLPG(addr)    __asm__ __volatile__ ("invlpg (%0)"::"r"(addr))
  58
  59 typedef Uint32  tTabEnt;
  60
  61 // === IMPORTS ===
  62 extern void     _UsertextEnd, _UsertextBase;
  63 extern Uint32   gaInitPageDir[1024];
  64 extern Uint32   gaInitPageTable[1024];
  65 extern void     Threads_SegFault(tVAddr Addr);
  66 extern void     Error_Backtrace(Uint eip, Uint ebp);
  67
  68 // === PROTOTYPES ===
  69 void    MM_PreinitVirtual(void);
  70 void    MM_InstallVirtual(void);
  71 void    MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs);
  72 void    MM_DumpTables(tVAddr Start, tVAddr End);
  73 tVAddr  MM_ClearUser(void);
  74 tPAddr  MM_DuplicatePage(tVAddr VAddr);
  75
  76 // === GLOBALS ===
  77 #define gaPageTable     ((tTabEnt*)PAGE_TABLE_ADDR)
  78 #define gaPageDir       ((tTabEnt*)PAGE_DIR_ADDR)
  79 #define gaTmpTable      ((tTabEnt*)TMP_TABLE_ADDR)
  80 #define gaTmpDir        ((tTabEnt*)TMP_DIR_ADDR)
  81 #define gpPageCR3       ((tTabEnt*)PAGE_CR3_ADDR)
  82 #define gpTmpCR3        ((tTabEnt*)TMP_CR3_ADDR)
  83
  84 #define gaPAE_PageTable ((tTabEnt*)PAE_PAGE_TABLE_ADDR)
  85 #define gaPAE_PageDir   ((tTabEnt*)PAE_PAGE_DIR_ADDR)
  86 #define gaPAE_MainPDPT  ((tTabEnt*)PAE_PAGE_PDPT_ADDR)
  87 #define gaPAE_TmpTable  ((tTabEnt*)PAE_TMP_DIR_ADDR)
  88 #define gaPAE_TmpDir    ((tTabEnt*)PAE_TMP_DIR_ADDR)
  89 #define gaPAE_TmpPDPT   ((tTabEnt*)PAE_TMP_PDPT_ADDR)
  90  int    gbUsePAE = 0;
  91 tMutex  glTempMappings;
  92 tMutex  glTempFractal;
  93 Uint32  gWorkerStacks[(NUM_WORKER_STACKS+31)/32];
  94  int    giLastUsedWorker = 0;
  95 struct sPageInfo {
  96         void    *Node;
  97         tVAddr  Base;
  98         Uint64  Offset;
  99          int    Length;
 100          int    Flags;
 101 }       *gaMappedRegions;       // sizeof = 24 bytes
 102
 103 // === CODE ===
 104 /**
 105  * \fn void MM_PreinitVirtual(void)
 106  * \brief Maps the fractal mappings
 107  */
 108 void MM_PreinitVirtual(void)
 109 {
 110         gaInitPageDir[ PAGE_TABLE_ADDR >> 22 ] = ((tTabEnt)&gaInitPageDir - KERNEL_BASE) | 3;
 111         INVLPG( PAGE_TABLE_ADDR );
 112 }
 113
 114 /**
 115  * \fn void MM_InstallVirtual(void)
 116  * \brief Sets up the constant page mappings
 117  */
 118 void MM_InstallVirtual(void)
 119 {
 120          int    i;
 121
 122         // --- Pre-Allocate kernel tables
 123         for( i = KERNEL_BASE>>22; i < 1024; i ++ )
 124         {
 125                 if( gaPageDir[ i ] )    continue;
 126                 // Skip stack tables, they are process unique
 127                 if( i > KERNEL_STACKS >> 22 && i < KERNEL_STACKS_END >> 22) {
 128                         gaPageDir[ i ] = 0;
 129                         continue;
 130                 }
 131                 // Preallocate table
 132                 gaPageDir[ i ] = MM_AllocPhys() | 3;
 133                 INVLPG( &gaPageTable[i*1024] );
 134                 memset( &gaPageTable[i*1024], 0, 0x1000 );
 135         }
 136
 137         // Unset kernel on the User Text pages
 138         for( i = ((tVAddr)&_UsertextEnd-(tVAddr)&_UsertextBase+0xFFF)/4096; i--; ) {
 139                 MM_SetFlags( (tVAddr)&_UsertextBase + i*4096, 0, MM_PFLAG_KERNEL );
 140         }
 141 }
 142
 143 /**
 144  * \brief Cleans up the SMP required mappings
 145  */
 146 void MM_FinishVirtualInit(void)
 147 {
 148         gaInitPageDir[ 0 ] = 0;
 149 }
 150
 151 /**
 152  * \fn void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 153  * \brief Called on a page fault
 154  */
 155 void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 156 {
 157         //ENTER("xAddr bErrorCode", Addr, ErrorCode);
 158
 159         // -- Check for COW --
 160         if( gaPageDir  [Addr>>22] & PF_PRESENT  && gaPageTable[Addr>>12] & PF_PRESENT
 161          && gaPageTable[Addr>>12] & PF_COW )
 162         {
 163                 tPAddr  paddr;
 164                 if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 1)
 165                 {
 166                         gaPageTable[Addr>>12] &= ~PF_COW;
 167                         gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
 168                 }
 169                 else
 170                 {
 171                         //Log("MM_PageFault: COW - MM_DuplicatePage(0x%x)", Addr);
 172                         paddr = MM_DuplicatePage( Addr );
 173                         MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
 174                         gaPageTable[Addr>>12] &= PF_USER;
 175                         gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
 176                 }
 177
 178                 Log_Debug("MMVirt", "COW for %p", Addr);
 179
 180                 INVLPG( Addr & ~0xFFF );
 181                 return;
 182         }
 183
 184         // If it was a user, tell the thread handler
 185         if(ErrorCode & 4) {
 186                 Log_Warning("MMVirt", "%s %s %s memory%s",
 187                         (ErrorCode&4?"User":"Kernel"),
 188                         (ErrorCode&2?"write to":"read from"),
 189                         (ErrorCode&1?"bad/locked":"non-present"),
 190                         (ErrorCode&16?" (Instruction Fetch)":"")
 191                         );
 192                 Warning("User Pagefault: Instruction at %04x:%08x accessed %p", Regs->cs, Regs->eip, Addr);
 193                 __asm__ __volatile__ ("sti");   // Restart IRQs
 194                 #if 1
 195                 Error_Backtrace(Regs->eip, Regs->ebp);
 196                 #endif
 197                 Threads_SegFault(Addr);
 198                 return ;
 199         }
 200
 201         Debug_KernelPanic();
 202
 203         // -- Check Error Code --
 204         if(ErrorCode & 8)
 205                 Warning("Reserved Bits Trashed!");
 206         else
 207         {
 208                 Warning("%s %s %s memory%s",
 209                         (ErrorCode&4?"User":"Kernel"),
 210                         (ErrorCode&2?"write to":"read from"),
 211                         (ErrorCode&1?"bad/locked":"non-present"),
 212                         (ErrorCode&16?" (Instruction Fetch)":"")
 213                         );
 214         }
 215
 216         Log("Code at %p accessed %p", Regs->eip, Addr);
 217         // Print Stack Backtrace
 218         Error_Backtrace(Regs->eip, Regs->ebp);
 219
 220         Log("gaPageDir[0x%x] = 0x%x", Addr>>22, gaPageDir[Addr>>22]);
 221         if( gaPageDir[Addr>>22] & PF_PRESENT )
 222                 Log("gaPageTable[0x%x] = 0x%x", Addr>>12, gaPageTable[Addr>>12]);
 223
 224         //MM_DumpTables(0, -1);
 225
 226         // Register Dump
 227         Log("EAX %08x ECX %08x EDX %08x EBX %08x", Regs->eax, Regs->ecx, Regs->edx, Regs->ebx);
 228         Log("ESP %08x EBP %08x ESI %08x EDI %08x", Regs->esp, Regs->ebp, Regs->esi, Regs->edi);
 229         //Log("SS:ESP %04x:%08x", Regs->ss, Regs->esp);
 230         Log("CS:EIP %04x:%08x", Regs->cs, Regs->eip);
 231         Log("DS %04x ES %04x FS %04x GS %04x", Regs->ds, Regs->es, Regs->fs, Regs->gs);
 232         {
 233                 Uint    dr0, dr1;
 234                 __ASM__ ("mov %%dr0, %0":"=r"(dr0):);
 235                 __ASM__ ("mov %%dr1, %0":"=r"(dr1):);
 236                 Log("DR0 %08x DR1 %08x", dr0, dr1);
 237         }
 238
 239         Panic("Page Fault at 0x%x (Accessed 0x%x)", Regs->eip, Addr);
 240 }
 241
 242 /**
 243  * \fn void MM_DumpTables(tVAddr Start, tVAddr End)
 244  * \brief Dumps the layout of the page tables
 245  */
 246 void MM_DumpTables(tVAddr Start, tVAddr End)
 247 {
 248         tVAddr  rangeStart = 0;
 249         tPAddr  expected = 0;
 250         void    *expected_node = NULL, *tmpnode = NULL;
 251         tVAddr  curPos;
 252         Uint    page;
 253         const tPAddr    MASK = ~0xF78;
 254
 255         Start >>= 12;   End >>= 12;
 256
 257         #if 0
 258         Log("Directory Entries:");
 259         for(page = Start >> 10;
 260                 page < (End >> 10)+1;
 261                 page ++)
 262         {
 263                 if(gaPageDir[page])
 264                 {
 265                         Log(" 0x%08x-0x%08x :: 0x%08x",
 266                                 page<<22, ((page+1)<<22)-1,
 267                                 gaPageDir[page]&~0xFFF
 268                                 );
 269                 }
 270         }
 271         #endif
 272
 273         Log("Table Entries:");
 274         for(page = Start, curPos = Start<<12;
 275                 page < End;
 276                 curPos += 0x1000, page++)
 277         {
 278                 if( !(gaPageDir[curPos>>22] & PF_PRESENT)
 279                 ||  !(gaPageTable[page] & PF_PRESENT)
 280                 ||  (gaPageTable[page] & MASK) != expected
 281                 ||  (tmpnode=NULL,MM_GetPageNode(curPos, &tmpnode), tmpnode != expected_node))
 282                 {
 283                         if(expected) {
 284                                 tPAddr  orig = gaPageTable[rangeStart>>12];
 285                                 Log(" 0x%08x => 0x%08x - 0x%08x (%s%s%s%s%s) %p",
 286                                         rangeStart,
 287                                         orig & ~0xFFF,
 288                                         curPos - rangeStart,
 289                                         (orig & PF_NOPAGE ? "P" : "-"),
 290                                         (orig & PF_COW ? "C" : "-"),
 291                                         (orig & PF_GLOBAL ? "G" : "-"),
 292                                         (orig & PF_USER ? "U" : "-"),
 293                                         (orig & PF_WRITE ? "W" : "-"),
 294                                         expected_node
 295                                         );
 296                                 expected = 0;
 297                         }
 298                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 299                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 300
 301                         expected = (gaPageTable[page] & MASK);
 302                         MM_GetPageNode(curPos, &expected_node);
 303                         rangeStart = curPos;
 304                 }
 305                 if(expected)    expected += 0x1000;
 306         }
 307
 308         if(expected) {
 309                 tPAddr  orig = gaPageTable[rangeStart>>12];
 310                 Log("0x%08x => 0x%08x - 0x%08x (%s%s%s%s%s) %p",
 311                         rangeStart,
 312                         orig & ~0xFFF,
 313                         curPos - rangeStart,
 314                         (orig & PF_NOPAGE ? "p" : "-"),
 315                         (orig & PF_COW ? "C" : "-"),
 316                         (orig & PF_GLOBAL ? "G" : "-"),
 317                         (orig & PF_USER ? "U" : "-"),
 318                         (orig & PF_WRITE ? "W" : "-"),
 319                         expected_node
 320                         );
 321                 expected = 0;
 322         }
 323 }
 324
 325 /**
 326  * \fn tPAddr MM_Allocate(tVAddr VAddr)
 327  */
 328 tPAddr MM_Allocate(tVAddr VAddr)
 329 {
 330         tPAddr  paddr;
 331         //ENTER("xVAddr", VAddr);
 332         //__asm__ __volatile__ ("xchg %bx,%bx");
 333         // Check if the directory is mapped
 334         if( gaPageDir[ VAddr >> 22 ] == 0 )
 335         {
 336                 // Allocate directory
 337                 paddr = MM_AllocPhys();
 338                 if( paddr == 0 ) {
 339                         Warning("MM_Allocate - Out of Memory (Called by %p)", __builtin_return_address(0));
 340                         //LEAVE('i',0);
 341                         return 0;
 342                 }
 343                 // Map and mark as user (if needed)
 344                 gaPageDir[ VAddr >> 22 ] = paddr | 3;
 345                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 346
 347                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 348                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 349         }
 350         // Check if the page is already allocated
 351         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 352                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 353                 //LEAVE('X', gaPageTable[ VAddr >> 12 ] & ~0xFFF);
 354                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 355         }
 356
 357         // Allocate
 358         paddr = MM_AllocPhys();
 359         //LOG("paddr = 0x%llx", paddr);
 360         if( paddr == 0 ) {
 361                 Warning("MM_Allocate - Out of Memory when allocating at %p (Called by %p)",
 362                         VAddr, __builtin_return_address(0));
 363                 //LEAVE('i',0);
 364                 return 0;
 365         }
 366         // Map
 367         gaPageTable[ VAddr >> 12 ] = paddr | 3;
 368         // Mark as user
 369         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 370         // Invalidate Cache for address
 371         INVLPG( VAddr & ~0xFFF );
 372
 373         //LEAVE('X', paddr);
 374         return paddr;
 375 }
 376
 377 /**
 378  * \fn void MM_Deallocate(tVAddr VAddr)
 379  */
 380 void MM_Deallocate(tVAddr VAddr)
 381 {
 382         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 383                 Warning("MM_Deallocate - Directory not mapped");
 384                 return;
 385         }
 386
 387         if(gaPageTable[ VAddr >> 12 ] == 0) {
 388                 Warning("MM_Deallocate - Page is not allocated");
 389                 return;
 390         }
 391
 392         // Dereference page
 393         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 394         // Clear page
 395         gaPageTable[ VAddr >> 12 ] = 0;
 396 }
 397
 398 /**
 399  * \fn tPAddr MM_GetPhysAddr(tVAddr Addr)
 400  * \brief Checks if the passed address is accesable
 401  */
 402 tPAddr MM_GetPhysAddr(tVAddr Addr)
 403 {
 404         if( !(gaPageDir[Addr >> 22] & 1) )
 405                 return 0;
 406         if( !(gaPageTable[Addr >> 12] & 1) )
 407                 return 0;
 408         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 409 }
 410
 411 /**
 412  * \fn void MM_SetCR3(Uint CR3)
 413  * \brief Sets the current process space
 414  */
 415 void MM_SetCR3(Uint CR3)
 416 {
 417         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 418 }
 419
 420 /**
 421  * \fn int MM_Map(tVAddr VAddr, tPAddr PAddr)
 422  * \brief Map a physical page to a virtual one
 423  */
 424 int MM_Map(tVAddr VAddr, tPAddr PAddr)
 425 {
 426         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 427         // Sanity check
 428         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 429                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 430                 //LEAVE('i', 0);
 431                 return 0;
 432         }
 433
 434         // Align addresses
 435         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 436
 437         // Check if the directory is mapped
 438         if( gaPageDir[ VAddr >> 22 ] == 0 )
 439         {
 440                 tPAddr  tmp = MM_AllocPhys();
 441                 if( tmp == 0 )
 442                         return 0;
 443                 gaPageDir[ VAddr >> 22 ] = tmp | 3;
 444
 445                 // Mark as user
 446                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 447
 448                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 449                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 450         }
 451         // Check if the page is already allocated
 452         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 453                 Warning("MM_Map - Allocating to used address");
 454                 //LEAVE('i', 0);
 455                 return 0;
 456         }
 457
 458         // Map
 459         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 460         // Mark as user
 461         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 462
 463         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 464         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 465
 466         // Reference
 467         MM_RefPhys( PAddr );
 468
 469         //LOG("INVLPG( 0x%x )", VAddr);
 470         INVLPG( VAddr );
 471
 472         //LEAVE('i', 1);
 473         return 1;
 474 }
 475
 476 /**
 477  * \fn tVAddr MM_ClearUser()
 478  * \brief Clear user's address space
 479  */
 480 tVAddr MM_ClearUser(void)
 481 {
 482         Uint    i, j;
 483
 484         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 485         {
 486                 // Check if directory is not allocated
 487                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 488                         gaPageDir[i] = 0;
 489                         continue;
 490                 }
 491
 492                 // Deallocate tables
 493                 for( j = 0; j < 1024; j ++ )
 494                 {
 495                         if( gaPageTable[i*1024+j] & 1 )
 496                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 497                         gaPageTable[i*1024+j] = 0;
 498                 }
 499
 500                 // Deallocate directory
 501                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 502                 gaPageDir[i] = 0;
 503                 INVLPG( &gaPageTable[i*1024] );
 504         }
 505         INVLPG( gaPageDir );
 506
 507         return *gpPageCR3;
 508 }
 509
 510 /**
 511  * \fn tPAddr MM_Clone(void)
 512  * \brief Clone the current address space
 513  */
 514 tPAddr MM_Clone(void)
 515 {
 516         Uint    i, j;
 517         tVAddr  ret;
 518         Uint    page = 0;
 519         tVAddr  kStackBase = Proc_GetCurThread()->KernelStack - KERNEL_STACK_SIZE;
 520         void    *tmp;
 521
 522         Mutex_Acquire( &glTempFractal );
 523
 524         // Create Directory Table
 525         *gpTmpCR3 = MM_AllocPhys() | 3;
 526         if( *gpTmpCR3 == 3 ) {
 527                 *gpTmpCR3 = 0;
 528                 return 0;
 529         }
 530         INVLPG( gaTmpDir );
 531         //LOG("Allocated Directory (%x)", *gpTmpCR3);
 532         memsetd( gaTmpDir, 0, 1024 );
 533
 534         if( Threads_GetPID() != 0 )
 535         {
 536                 // Copy Tables
 537                 for( i = 0; i < 768; i ++)
 538                 {
 539                         // Check if table is allocated
 540                         if( !(gaPageDir[i] & PF_PRESENT) ) {
 541                                 gaTmpDir[i] = 0;
 542                                 page += 1024;
 543                                 continue;
 544                         }
 545
 546                         // Allocate new table
 547                         gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 548                         INVLPG( &gaTmpTable[page] );
 549                         // Fill
 550                         for( j = 0; j < 1024; j ++, page++ )
 551                         {
 552                                 if( !(gaPageTable[page] & PF_PRESENT) ) {
 553                                         gaTmpTable[page] = 0;
 554                                         continue;
 555                                 }
 556
 557                                 // Refrence old page
 558                                 MM_RefPhys( gaPageTable[page] & ~0xFFF );
 559                                 // Add to new table
 560                                 if(gaPageTable[page] & PF_WRITE) {
 561                                         gaTmpTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 562                                         gaPageTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 563                                         INVLPG( page << 12 );
 564                                 }
 565                                 else
 566                                         gaTmpTable[page] = gaPageTable[page];
 567                         }
 568                 }
 569         }
 570
 571         // Map in kernel tables (and make fractal mapping)
 572         for( i = 768; i < 1024; i ++ )
 573         {
 574                 // Fractal
 575                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 576                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gpTmpCR3;
 577                         continue;
 578                 }
 579
 580                 if( gaPageDir[i] == 0 ) {
 581                         gaTmpDir[i] = 0;
 582                         continue;
 583                 }
 584
 585                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 586                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 587                 gaTmpDir[i] = gaPageDir[i];
 588         }
 589
 590         // Allocate kernel stack
 591         for(i = KERNEL_STACKS >> 22;
 592                 i < KERNEL_STACKS_END >> 22;
 593                 i ++ )
 594         {
 595                 // Check if directory is allocated
 596                 if( (gaPageDir[i] & 1) == 0 ) {
 597                         gaTmpDir[i] = 0;
 598                         continue;
 599                 }
 600
 601                 // We don't care about other kernel stacks, just the current one
 602                 if( i != kStackBase >> 22 ) {
 603                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 604                         gaTmpDir[i] = 0;
 605                         continue;
 606                 }
 607
 608                 // Create a copy
 609                 gaTmpDir[i] = MM_AllocPhys() | 3;
 610                 INVLPG( &gaTmpTable[i*1024] );
 611                 for( j = 0; j < 1024; j ++ )
 612                 {
 613                         // Is the page allocated? If not, skip
 614                         if( !(gaPageTable[i*1024+j] & 1) ) {
 615                                 gaTmpTable[i*1024+j] = 0;
 616                                 continue;
 617                         }
 618
 619                         // We don't care about other kernel stacks
 620                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 621                                 gaTmpTable[i*1024+j] = 0;
 622                                 continue;
 623                         }
 624
 625                         // Allocate page
 626                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 627
 628                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 629
 630                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 631                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 632                         MM_FreeTemp( (Uint)tmp );
 633                 }
 634         }
 635
 636         ret = *gpTmpCR3 & ~0xFFF;
 637         Mutex_Release( &glTempFractal );
 638
 639         //LEAVE('x', ret);
 640         return ret;
 641 }
 642
 643 /**
 644  * \fn tVAddr MM_NewKStack(void)
 645  * \brief Create a new kernel stack
 646  */
 647 tVAddr MM_NewKStack(void)
 648 {
 649         tVAddr  base;
 650         Uint    i;
 651         for(base = KERNEL_STACKS; base < KERNEL_STACKS_END; base += KERNEL_STACK_SIZE)
 652         {
 653                 // Check if space is free
 654                 if(MM_GetPhysAddr(base) != 0)   continue;
 655                 // Allocate
 656                 //for(i = KERNEL_STACK_SIZE; i -= 0x1000 ; )
 657                 for(i = 0; i < KERNEL_STACK_SIZE; i += 0x1000 )
 658                 {
 659                         if( MM_Allocate(base+i) == 0 )
 660                         {
 661                                 // On error, print a warning and return error
 662                                 Warning("MM_NewKStack - Out of memory");
 663                                 // - Clean up
 664                                 //for( i += 0x1000 ; i < KERNEL_STACK_SIZE; i += 0x1000 )
 665                                 //      MM_Deallocate(base+i);
 666                                 return 0;
 667                         }
 668                 }
 669                 // Success
 670                 Log("MM_NewKStack - Allocated %p", base + KERNEL_STACK_SIZE);
 671                 return base+KERNEL_STACK_SIZE;
 672         }
 673         // No stacks left
 674         Warning("MM_NewKStack - No address space left");
 675         return 0;
 676 }
 677
 678 /**
 679  * \fn tVAddr MM_NewWorkerStack()
 680  * \brief Creates a new worker stack
 681  */
 682 tVAddr MM_NewWorkerStack()
 683 {
 684         Uint    esp, ebp;
 685         Uint    oldstack;
 686         Uint    base, addr;
 687          int    i, j;
 688         Uint    *tmpPage;
 689         tPAddr  pages[WORKER_STACK_SIZE>>12];
 690
 691         // Get the old ESP and EBP
 692         __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
 693         __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
 694
 695         // TODO: Thread safety
 696         // Find a free worker stack address
 697         for(base = giLastUsedWorker; base < NUM_WORKER_STACKS; base++)
 698         {
 699                 // Used block
 700                 if( gWorkerStacks[base/32] == -1 ) {
 701                         base += 31;     base &= ~31;
 702                         base --;        // Counteracted by the base++
 703                         continue;
 704                 }
 705                 // Used stack
 706                 if( gWorkerStacks[base/32] & (1 << base) ) {
 707                         continue;
 708                 }
 709                 break;
 710         }
 711         if(base >= NUM_WORKER_STACKS) {
 712                 Warning("Uh-oh! Out of worker stacks");
 713                 return 0;
 714         }
 715
 716         // It's ours now!
 717         gWorkerStacks[base/32] |= (1 << base);
 718         // Make life easier for later calls
 719         giLastUsedWorker = base;
 720         // We have one
 721         base = WORKER_STACKS + base * WORKER_STACK_SIZE;
 722         //Log(" MM_NewWorkerStack: base = 0x%x", base);
 723
 724         // Acquire the lock for the temp fractal mappings
 725         Mutex_Acquire(&glTempFractal);
 726
 727         // Set the temp fractals to TID0's address space
 728         *gpTmpCR3 = ((Uint)gaInitPageDir - KERNEL_BASE) | 3;
 729         //Log(" MM_NewWorkerStack: *gpTmpCR3 = 0x%x", *gpTmpCR3);
 730         INVLPG( gaTmpDir );
 731
 732
 733         // Check if the directory is mapped (we are assuming that the stacks
 734         // will fit neatly in a directory)
 735         //Log(" MM_NewWorkerStack: gaTmpDir[ 0x%x ] = 0x%x", base>>22, gaTmpDir[ base >> 22 ]);
 736         if(gaTmpDir[ base >> 22 ] == 0) {
 737                 gaTmpDir[ base >> 22 ] = MM_AllocPhys() | 3;
 738                 INVLPG( &gaTmpTable[ (base>>12) & ~0x3FF ] );
 739         }
 740
 741         // Mapping Time!
 742         for( addr = 0; addr < WORKER_STACK_SIZE; addr += 0x1000 )
 743         //for( addr = WORKER_STACK_SIZE; addr; addr -= 0x1000 )
 744         {
 745                 pages[ addr >> 12 ] = MM_AllocPhys();
 746                 gaTmpTable[ (base + addr) >> 12 ] = pages[addr>>12] | 3;
 747         }
 748         *gpTmpCR3 = 0;
 749         // Release the temp mapping lock
 750         Mutex_Release(&glTempFractal);
 751
 752         // Copy the old stack
 753         oldstack = (esp + KERNEL_STACK_SIZE-1) & ~(KERNEL_STACK_SIZE-1);
 754         esp = oldstack - esp;   // ESP as an offset in the stack
 755
 756         // Make `base` be the top of the stack
 757         base += WORKER_STACK_SIZE;
 758
 759         i = (WORKER_STACK_SIZE>>12) - 1;
 760         // Copy the contents of the old stack to the new one, altering the addresses
 761         // `addr` is refering to bytes from the stack base (mem downwards)
 762         for(addr = 0; addr < esp; addr += 0x1000)
 763         {
 764                 Uint    *stack = (Uint*)( oldstack-(addr+0x1000) );
 765                 tmpPage = (void*)MM_MapTemp( pages[i] );
 766                 // Copy old stack
 767                 for(j = 0; j < 1024; j++)
 768                 {
 769                         // Possible Stack address?
 770                         if(oldstack-esp < stack[j] && stack[j] < oldstack)
 771                                 tmpPage[j] = base - (oldstack - stack[j]);
 772                         else    // Seems not, best leave it alone
 773                                 tmpPage[j] = stack[j];
 774                 }
 775                 MM_FreeTemp((tVAddr)tmpPage);
 776                 i --;
 777         }
 778
 779         //Log("MM_NewWorkerStack: RETURN 0x%x", base);
 780         return base;
 781 }
 782
 783 /**
 784  * \fn void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 785  * \brief Sets the flags on a page
 786  */
 787 void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 788 {
 789         tTabEnt *ent;
 790         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 791         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 792
 793         ent = &gaPageTable[VAddr >> 12];
 794
 795         // Read-Only
 796         if( Mask & MM_PFLAG_RO )
 797         {
 798                 if( Flags & MM_PFLAG_RO ) {
 799                         *ent &= ~PF_WRITE;
 800                 }
 801                 else {
 802                         gaPageDir[VAddr >> 22] |= PF_WRITE;
 803                         *ent |= PF_WRITE;
 804                 }
 805         }
 806
 807         // Kernel
 808         if( Mask & MM_PFLAG_KERNEL )
 809         {
 810                 if( Flags & MM_PFLAG_KERNEL ) {
 811                         *ent &= ~PF_USER;
 812                 }
 813                 else {
 814                         gaPageDir[VAddr >> 22] |= PF_USER;
 815                         *ent |= PF_USER;
 816                 }
 817         }
 818
 819         // Copy-On-Write
 820         if( Mask & MM_PFLAG_COW )
 821         {
 822                 if( Flags & MM_PFLAG_COW ) {
 823                         *ent &= ~PF_WRITE;
 824                         *ent |= PF_COW;
 825                 }
 826                 else {
 827                         *ent &= ~PF_COW;
 828                         *ent |= PF_WRITE;
 829                 }
 830         }
 831
 832         //Log("MM_SetFlags: *ent = 0x%08x, gaPageDir[%i] = 0x%08x",
 833         //      *ent, VAddr >> 22, gaPageDir[VAddr >> 22]);
 834 }
 835
 836 /**
 837  * \brief Get the flags on a page
 838  */
 839 Uint MM_GetFlags(tVAddr VAddr)
 840 {
 841         tTabEnt *ent;
 842         Uint    ret = 0;
 843
 844         // Validity Check
 845         if( !(gaPageDir[VAddr >> 22] & 1) )     return 0;
 846         if( !(gaPageTable[VAddr >> 12] & 1) )   return 0;
 847
 848         ent = &gaPageTable[VAddr >> 12];
 849
 850         // Read-Only
 851         if( !(*ent & PF_WRITE) )        ret |= MM_PFLAG_RO;
 852         // Kernel
 853         if( !(*ent & PF_USER) ) ret |= MM_PFLAG_KERNEL;
 854         // Copy-On-Write
 855         if( *ent & PF_COW )     ret |= MM_PFLAG_COW;
 856
 857         return ret;
 858 }
 859
 860 /**
 861  * \fn tPAddr MM_DuplicatePage(tVAddr VAddr)
 862  * \brief Duplicates a virtual page to a physical one
 863  */
 864 tPAddr MM_DuplicatePage(tVAddr VAddr)
 865 {
 866         tPAddr  ret;
 867         Uint    temp;
 868          int    wasRO = 0;
 869
 870         //ENTER("xVAddr", VAddr);
 871
 872         // Check if mapped
 873         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 874         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 875
 876         // Page Align
 877         VAddr &= ~0xFFF;
 878
 879         // Allocate new page
 880         ret = MM_AllocPhys();
 881         if( !ret ) {
 882                 return 0;
 883         }
 884
 885         // Write-lock the page (to keep data constistent), saving its R/W state
 886         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 887         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 888         INVLPG( VAddr );
 889
 890         // Copy Data
 891         temp = MM_MapTemp(ret);
 892         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 893         MM_FreeTemp(temp);
 894
 895         // Restore Writeable status
 896         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 897         INVLPG(VAddr);
 898
 899         //LEAVE('X', ret);
 900         return ret;
 901 }
 902
 903 /**
 904  * \fn Uint MM_MapTemp(tPAddr PAddr)
 905  * \brief Create a temporary memory mapping
 906  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 907  */
 908 tVAddr MM_MapTemp(tPAddr PAddr)
 909 {
 910          int    i;
 911
 912         //ENTER("XPAddr", PAddr);
 913
 914         PAddr &= ~0xFFF;
 915
 916         //LOG("glTempMappings = %i", glTempMappings);
 917
 918         for(;;)
 919         {
 920                 Mutex_Acquire( &glTempMappings );
 921
 922                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 923                 {
 924                         // Check if page used
 925                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 926                         // Mark as used
 927                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 928                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 929                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 930                         Mutex_Release( &glTempMappings );
 931                         return TEMP_MAP_ADDR + (i << 12);
 932                 }
 933                 Mutex_Release( &glTempMappings );
 934                 Threads_Yield();        // TODO: Use a sleep queue here instead
 935         }
 936 }
 937
 938 /**
 939  * \fn void MM_FreeTemp(tVAddr PAddr)
 940  * \brief Free's a temp mapping
 941  */
 942 void MM_FreeTemp(tVAddr VAddr)
 943 {
 944          int    i = VAddr >> 12;
 945         //ENTER("xVAddr", VAddr);
 946
 947         if(i >= (TEMP_MAP_ADDR >> 12))
 948                 gaPageTable[ i ] = 0;
 949
 950         //LEAVE('-');
 951 }
 952
 953 /**
 954  * \fn tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 955  * \brief Allocates a contigous number of pages
 956  */
 957 tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 958 {
 959          int    i, j;
 960
 961         PAddr &= ~0xFFF;
 962
 963         // Scan List
 964         for( i = 0; i < NUM_HW_PAGES; i ++ )
 965         {
 966                 // Check if addr used
 967                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 968                         continue;
 969
 970                 // Check possible region
 971                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 972                 {
 973                         // If there is an allocated page in the region we are testing, break
 974                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 975                 }
 976                 // Is it all free?
 977                 if( j == Number )
 978                 {
 979                         // Allocate
 980                         for( j = 0; j < Number; j++ ) {
 981                                 MM_RefPhys( PAddr + (j<<12) );
 982                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 983                         }
 984                         return HW_MAP_ADDR + (i<<12);
 985                 }
 986         }
 987         // If we don't find any, return NULL
 988         return 0;
 989 }
 990
 991 /**
 992  * \fn tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
 993  * \brief Allocates DMA physical memory
 994  * \param Pages Number of pages required
 995  * \param MaxBits       Maximum number of bits the physical address can have
 996  * \param PhysAddr      Pointer to the location to place the physical address allocated
 997  * \return Virtual address allocate
 998  */
 999 tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
1000 {
1001         tPAddr  maxCheck = (1 << MaxBits);
1002         tPAddr  phys;
1003         tVAddr  ret;
1004
1005         ENTER("iPages iMaxBits pPhysAddr", Pages, MaxBits, PhysAddr);
1006
1007         // Sanity Check
1008         if(MaxBits < 12 || !PhysAddr) {
1009                 LEAVE('i', 0);
1010                 return 0;
1011         }
1012
1013         // Bound
1014         if(MaxBits >= PHYS_BITS)        maxCheck = -1;
1015
1016         // Fast Allocate
1017         if(Pages == 1 && MaxBits >= PHYS_BITS)
1018         {
1019                 phys = MM_AllocPhys();
1020                 if( !phys ) {
1021                         *PhysAddr = 0;
1022                         LEAVE_RET('i', 0);
1023                 }
1024                 *PhysAddr = phys;
1025                 ret = MM_MapHWPages(phys, 1);
1026                 if(ret == 0) {
1027                         MM_DerefPhys(phys);
1028                         LEAVE('i', 0);
1029                         return 0;
1030                 }
1031                 LEAVE('x', ret);
1032                 return ret;
1033         }
1034
1035         // Slow Allocate
1036         phys = MM_AllocPhysRange(Pages, MaxBits);
1037         // - Was it allocated?
1038         if(phys == 0) {
1039                 LEAVE('i', 0);
1040                 return 0;
1041         }
1042
1043         // Allocated successfully, now map
1044         ret = MM_MapHWPages(phys, Pages);
1045         if( ret == 0 ) {
1046                 // If it didn't map, free then return 0
1047                 for(;Pages--;phys+=0x1000)
1048                         MM_DerefPhys(phys);
1049                 LEAVE('i', 0);
1050                 return 0;
1051         }
1052
1053         *PhysAddr = phys;
1054         LEAVE('x', ret);
1055         return ret;
1056 }
1057
1058 /**
1059  * \fn void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1060  * \brief Unmap a hardware page
1061  */
1062 void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1063 {
1064          int    i, j;
1065
1066         //Log_Debug("VirtMem", "MM_UnmapHWPages: (VAddr=0x%08x, Number=%i)", VAddr, Number);
1067
1068         // Sanity Check
1069         if(VAddr < HW_MAP_ADDR || VAddr+Number*0x1000 > HW_MAP_MAX)     return;
1070
1071         i = VAddr >> 12;
1072
1073         Mutex_Acquire( &glTempMappings );       // Temp and HW share a directory, so they share a lock
1074
1075         for( j = 0; j < Number; j++ )
1076         {
1077                 MM_DerefPhys( gaPageTable[ i + j ] & ~0xFFF );
1078                 gaPageTable[ i + j ] = 0;
1079         }
1080
1081         Mutex_Release( &glTempMappings );
1082 }
1083